Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!

 


Forgot your password?
Close
typodupeerror
×
Shark Science

Florida Researchers Create Shortest Light Pulse Ever Recorded 76

Posted by timothy from the don't-blink-or-you'll-miss-it dept.
SchrodingerZ writes "Researchers at the University of Central Florida have created the shortest laser pulse ever recorded, lasting only 67 attoseconds. An attosecond is a mere quintillionith of a single second (1/1,000,000,000,000,000,000). The record-breaking project was run by UCF Professor Zenghu Chang, using an extreme ultraviolet laser pulse. '"Dr. Chang's success in making ever-shorter light pulses helps open a new door to a previously hidden world, where we can watch electrons move in atoms and molecules, and follow chemical reactions as they take place," said Michael Johnson, the dean of the UCF College of Sciences and a physicist.' Its hoped that these short laser blasts will pave the way to better understand quantum mechanics in ways we have never before witnessed. In 2008 the previous record was set at 80 attoseconds, the pulse created at the Max Planck Institute in Garching, Germany."
This discussion has been archived. No new comments can be posted.

Florida Researchers Create Shortest Light Pulse Ever Recorded More

Florida Researchers Create Shortest Light Pulse Ever Recorded

Comments Filter:

  • The width of a virus (Score:5, Informative)

    by hawguy ( 1600213 ) on Thursday September 06, 2012 @05:01PM (#41254037)

    To put that in perspective, light in a vacuum travels around 20 nm [google.com] in 67 attoseconds, so the width of the pulse is about the same as the width of the smallest virus [blogspot.com] or about 1/350th the 7um [wikipedia.org] diameter of a human blood cell.

  • Now lets see what these little buggers look like in their own respective slow motion. Careful not to give the quarks any seizures.

  • longer than my attention span

  • How do you even measure this? (Score:1)

    by Anonymous Coward

    How do you even measure something of such short duration? Is it an interpolated result?

  • I can create a laser pulse lasting ZERO attoseconds. There, just did it. There, just did it again. Top *that*, UCF!

  • How do they measure this? (Score:4, Interesting)

    by PhrostyMcByte ( 589271 ) <phrosty@gmail.com> on Thursday September 06, 2012 @05:12PM (#41254159) Homepage
    Can anyone explain how they accurately measure time spans this small? Or did they not measure at all, and instead calculate what it should be from other parameters?

    • Re: (Score:1)

      by harrkev ( 623093 )

      Also, how powerful was the pulse?

      It is EASY to create the world's shortest laser pulse: emit a single photon. It is monochromatic, coherent (so it meets the laser defninition), and has the shortest possible pulse. Of course, one single photon is not really good for much, You really need a lot of photons to do anything useful.

      • It is EASY to create the world's shortest laser pulse: emit a single photon. It is monochromatic, coherent (so it meets the laser defninition), and has the shortest possible pulse. .

        No, by cleverly combining multiple photons of different frequencies you can produce a pulse that concentrates its energy in a shorter timespan. Calling it a laser pulse is actually stretching a point a bit, it is triggered by laser light, but the pulse itself is not monochromatic.

        • I think the interesting part of this is that this laser pulse is no longer than approximately 2 wavelengths.

          Wikipedia tells me "extreme ultraviolet" is from 120nm to 10nm. Google tells me "(the speed of light / (10 nm)) * (67 attoseconds)" is 2.0086094686.

          Wow. Just wow.

        • Re: (Score:2)

          by JoeRobe ( 207552 )

          Monochromatic is not a prerequisite for laser light. Coherence and leverage of a population inversion are requirements for it to be laser light, with the latter being sometimes loosely applied. This pulse is as much a laser emission as that from any other, because it is coherent. Laser emission can come from continuous wave lasers (like most red laser pointers), which can be incredibly monochromatic (sub-MHz bandwidth) or from pulsed lasers, which can be incredibly non-monochromatic (many nanometers bandw

      • Re:How do they measure this? (Score:5, Interesting)

        by The Master Control P ( 655590 ) <ejkeever@nerdshac[ ]om ['k.c' in gap]> on Thursday September 06, 2012 @05:51PM (#41254537)
        A monochromatic wave, having zero extent in momentum space, has infinite extent in realspace.

        A laser pulse whose duration is comparable to a single wave period as those in TFA are will in fact have a very broad energy spectrum, which can be understood both through time-energy uncertainty and by noting that a pulse waveform has a broad fourier spectrum, corresponding to broad energy distribution.

        I end up saying or at least thinking this every time a science-breakthrough article comes by on Slashdot: If you think whatever someone did in cutting-edge experimental science is "easy," it's because you don't understand what they did and/or the theory behind it. Think before you speak: If it were actually easy, wouldn't they have already done it this way? Posting a "dumb scientists, that was easy" comment will bring only embarassment.

    • Re:How do they measure this? (Score:5, Informative)

      by Anonymous Coward on Thursday September 06, 2012 @05:35PM (#41254349)

      Short version: They use nonlinear optics and variable delay between two beam paths.

      The technique is called Frequency-Resolved Optical Gating [wikipedia.org] (there are a bunch of derived techniques used in specific cases, like the one here), and is actually a brilliant idea when you think about it. You measure the spectrogram of a nonlinear function of the pulse and itself with variable delay.

    • Re: (Score:1)

      by WSOGMM ( 1460481 )

      I won't explain it, as I don't feel like reading through all of it right now, but someone else is welcome to! And now it's easy to find.

      Emission of pulse:

      It's actually called Double optical Gating, not Grating, as the article called it. http://www.phys.ksu.edu/personal/chang/Chang-attoweb.pdf [ksu.edu]

      Detection: Phase Retrieval by Omega Oscillation Filtering

      http://www.creol.ucf.edu/research/publications/2859.pdf

    • ``In addition to creating the light pulse, he created an even faster camera to measure it, which is the Phase Retrieval by Omega Oscillation Filtering (PROOF).''

      • ``In addition to creating the light pulse, he created an even faster camera to measure it, which is the Phase Retrieval by Omega Oscillation Filtering (PROOF).''

        Apparently when he claimed that it was possible to image a single electron orbiting an atom his supervisor LAUGHED AT HIM and demanded PROOF.

        Insert i-double-dares-ya, scientist-rising-to-a-challenge, whoomp-there-it-is.

    • The basic technique involves splitting the pulse into two, sending each pulse down different paths, recombining them in such a way that a third pulse is generated whose strength is proportional to the overlap between the first two pulses. By varying the relative delay between the two pulse replicas, you change the final intensity, and you have mapped the spatial delay onto time delay and effectively measured the pulse. For such short pulses, there are some special tricks that are needed, and a bit of comput

  • Three New York Taxis and two bike couriers can get through the intersection during the duration of that light.

    • Re: (Score:2)

      by drkim ( 1559875 )

      Three New York Taxis and two bike couriers can get through the intersection during the duration of that light.

      Gedda fuq outta here! New York Taxis and bike couriers don't wait furda frickin' light.

  • 1/1,000,000,000,000,000,000. What does that mean? (Score:5, Interesting)

    by tim_darklighter ( 822987 ) on Thursday September 06, 2012 @05:18PM (#41254191)
    A word to the wise when trying to get people excited about fundmental science: the number "1" followed by a lot of zeroes is meaningless to most people (even scientists). Please give us something to relate that number to and put it in scientific notation!

    67 attoseconds = 6.7 x 10^–18 seconds

    As a photochemist, I know that a femtosecond is (1 x 10^–15 seconds) is the on order of many "fast" chemical reactions, like visible light reacting with your eye, so attoseconds are faster than most chemical bonds breaking/forming.

    • Re:1/1,000,000,000,000,000,000. What does that mea (Score:5, Insightful)

      by hawguy ( 1600213 ) on Thursday September 06, 2012 @05:38PM (#41254397)

      A word to the wise when trying to get people excited about fundmental science: the number "1" followed by a lot of zeroes is meaningless to most people (even scientists). Please give us something to relate that number to and put it in scientific notation!

      They did give a unit that scientists can relate to when they said "67 attoseconds". The 1/1,000,000,000,000,000,000 notation is just there for the layman for whom scientific notation means nothing, 1 x 10^-18 means little to most people, but lots of zeros make it clear that it's a very small number.

      67 attoseconds = 6.7 x 10^–18 seconds

      You're off by 10 -- 67 attoseconds = 67 x 10^-18, or 6.7 x 10^-17

      • You're off by a factor of 10 -- 67 attoseconds = 67 x 10^-18, or 6.7 x 10^-17

        I'll get my coat.

      • Bah. You got me on 6.7 x 10^-17 sec.

        My gripe is the OP's frame of reference: "an attosecond is 1/1,000,000,000,000,000,000 seconds". That would be like telling me that the Pacific Ocean holds 1,000,000,000,000,000,000 teaspoons of water. That value and that unit should never go together. Lots of zeroes (big or small) is mind-boggling for a layperson or scientist, especially since OP did not give any frame of reference like, "1000 times faster than your eyes turn light into images". It's not a perfect comp

        • Re: (Score:2)

          by fnj ( 64210 )

          The number is what it is. Sorry if it's not trivial to comprehend the number. That's not the writer/speaker's job. It's the reader/listener's job. It's a fair amount of work to do so, but really not that much. It's character building. I doubt if the brain has to spend more than a tiny fraction of a teaspoon of glucose and maybe a few thimblefuls of oxygen to work out a way to visualize it.

        • If someone isn't going to understand attoseconds then he can understand that its mindbogglingly short. That's where the 1/1,000,000,000,000,000,000 comes in. If you can understand attoseconds it seems useless information.
          You seem to be in a third group: you can't understand attoseconds, but the 1/1,000,000,000,000,000,000 is to layman-ish for you. You complain because you cannot understand that someone would neither understand attoseconds nor 6.7x10^-17 (of which there are many).
          Now I do agree with comp

    • Yes, nothing says "meaningful to most people" like some good old scientific notation... Do you get that 60% of the US doesn't have a college degree, much less multiple degrees, mr. smartass?

  • Atto-boy!!! (Score:3)

    by trout007 ( 975317 ) on Thursday September 06, 2012 @06:00PM (#41254633)

    Great job

  • Oh I mean can you send and receive data? Say over fiber optic at speeds like this? How about data over a lazar to (where?) say mars?

    I have no problems with basic science, Great science Guys. I am just wondering what is next? the Lab (FAST) is the Florida Atto Science & Technology (FAST). So the tech part is next.
  • How can they speculate about the color of the source (ultra-violet) when a single complete cycle of a wave of that color is 300-400nm long, and the pulse generated here was only 20 nm long?

    • Re: (Score:2, Informative)

      by Anonymous Coward

      If you know at what energy levels the photons are released, you know the wavelength.

  • "we can watch electrons move" - I thought quantum dynamics, and Heisenberg's uncertainty principle in particular, prohibits things like that? After all, watching something move essentially means you are able to measure both it's position and velocity?

Slashdot Top Deals

You are always doing something marginal when the boss drops by your desk.

Close